Toothed disk coupling of a shaft to a hub

ABSTRACT

In a positive releasable coupling comprising a shaft, a hub on said shaft, the shaft and hub having end faces lying in substantially the same plane and being provided with aligned slots cut into their end faces, a coupling disk provided with teeth complementing and engaging the slots of said shaft and said hub and thereby coupling said shaft to said hub, and means for securing said disk to at least one of said shaft and said hub, the improvement which comprises forming said disk as an annulus held against the ends of the shaft and hub by a cap secured to the shaft by a bolt. The disk is provided with radially directed wedge shaped teeth, the faces of the teeth in radial crosssection making about 45* angles with the plane defining the ends of the shaft and hub with the apex being located in the vicinity of the outside surface of the shaft; in cross-section tangenial to the shaft the teeth are tapered toward the shaft. The ends of the shaft and hub are slotted so as to mate with the teeth of the disk and are thereby coupled. Advantageously the disk is deformable between the teeth and is provided on its face adjacent the cap with spaced projections which constitute the points of contact therebetween.

[451 Sept. 25, 1973 TOOTHED DISK COUPLING OF A SHAFT TO A HUB [75]Inventor: Walter Schroder, Stemmannsfeld,

Germany [73] Assignee: WGW Westdeutsche Getriebewerke GmbH, l-lerne,Germany [22] Filed: Apr. 17, 1972 [21] Appl. No.: 244,814

[30] Foreign Application Priority Data Apr. 21, 1971 Germany P 21 19325.9

[52] U.S. Cl. 64/9, 64/14, 64/27 NM, 287/53 SS [51] int. Cl. Fl6d 3/18[58] Field of Search 64/9, 14, 6, 4, 5, 64/23, 27 NM; 287/53 SS, 53 R[56] References Cited UNlTEDSTATES PATENTS 1,759,338 5/1930 Allen 64/92,529,963 ll/l950 Prodromos..... 287/53 R 2,679,735 6/1954 Rowe 64/92,956,826 10/1960 Nord 287/53 R 3,314,318 Shoults 64/9 PrimaryExaminerCharles J. Myhre Assistant ExaminerRandall l-leald Att0rneyRalphD. Dinklage et al.

[5 7] ABSTRACT In a positive releasable coupling comprising a shaft, ahub on said shaft, the shaft and hub having end faces lying insubstantially the same plane and being provided with aligned slots cutinto their end faces, a coupling disk provided with teeth complementingand engaging the slots of said shaft and said hub and thereby couplingsaid shaft to said hub, and means for securing said disk to at least oneof said shaft and said hub, the improvement which comprises forming saiddisk as an annulus held against the ends of the shaft and hub by a capsecured to the shaft by a bolt. The disk is provided with radiallydirected wedge shaped teeth, the faces of the teeth in radialcross-section making'about 45 angles with the plane defining the ends ofthe shaft and hub with the apex being located in the vicinity of theoutside surface of the shaft; in cross-section tangenial to the shaftthe teeth are tapered toward the shaft. The ends of the shaft and hubare slotted so as to mate with the teeth of the disk and are therebycoupled. Advantageously the disk is deformable between the teeth and isprovided on its face adjacent the cap with spaced projections whichconstitute the points of contact therebetween.

8 Claims, 4 Drawing Figures PATENTEflsiPzslm SHEET 1 BF 2 lllllTOOTI-IED DISK COUPLING OF A SI-IAFI TO A HUB The invention relates to apositive, releasable coupling for the transmission of heavy torquebetween a solid shaft and a hub or hollow shaft.

To provide a coupling for rotation between a shaft and a hub or hollowshaft mounted thereon, springs are used in many cases where smalldiameters are involved. Where the hub is of larger diameter, such as adiameter in excess of 150 mm, friction-type coupling means are usuallyused, such as clamping elements, clamping sets or the like. Thesefriction-type coupling are in many cases disposed on the solid shaftwithin the hub. Such friction coupling means have the disadvantage thattheir internally located elements necessitate the recessing and hencethe weakening of the solid shaft; furthermore, access to them can beobtained from without only with difficulty. Since experience shows thatfriction junctions corrode in the course of time, along with theclamping elements, especially in the case of outdoor use, disassembly ofthe hub or hollow shaft, i.e., the removal of the hub. from the shaft,becomes difficult or even impossible. The result may be that the hubwill have to be forced off. Another disadvantage is that, with frictioncoupling means, slipping under high torque peaks cannot reliably beprevented.

Positive couplings are known in which special coupling eJements join theshaft and hub together by means of teeth. In one known coupling of thiskind, the ends of both the shaft and hub are provided with slots whichare engaged by the teeth of a disk. The disk is fastened to the end ofthe shaft by means of a bolt.

While such coupling is satisfactory for some purposes, it is an objectof the invention to provide a positive coupling which is even morereliable in transmitting heavy torques.

This and other objects and advantages are realized in accordance withthe present invention which relates to a coupling of the type describedcomprising a shaft, a hub on said shaft, the shaft and hub having endfaces lying in substantially the same plane and being provided withaligned slots cut into their end faces, a coupling disk provided withteeth complementing and engaging the slots of said shaft and said huband thereby coupling said shaft to said hub, and means for securing saiddisk to at least one of said shaft and said hub. The

novel feature resides in forming the teeth of the disk so that they aregenerally radially directed, said teeth in radial cross-section beingwedge-shaped, the apex of the wedge pointing toward said shaft and saidhub and being located in the vicinity of the outside surface of saidshaft. As a result of the wedge-shaped construction of the teeth, thebearing surface of each tooth is considerably increased withoutweakening the cross section of the shaft or hub, unlike axis-parallel oraxisperpendicular arrangements.

At the same time the teeth are given an especially high strength bytheir shape, which is especially important where the transfer of greatforces is involved. Furthermore, the slots can be milled into the endsof the shaft and hub or hollow shaft at not great expense.

Advantageously the coupling element is an annular disk which is fastenedby means of a cap or retaining means to the ends of the shaft and hub orhollow shaft. Advantageously, the heavily stressed coupling element canthus be manufactured separately without being made of high-quality andexpensive materials, being made, for example, in the form of a precisioncasting. A seal can be provided in the cap so as to protect the interiorof the coupling.

It is desirable for the wedge angle of the grooves and teeth to beapproximately i.e. for the inclined faces of the wedge in radialcross-section to make 45 angles with the plane in which the end faces ofthe shaft and hub lie. High axial stresses occur, which cause aresilient deformation of the coupling element in the axial direction andwhich thus enable the tooth surfaces to conform better to their matchingrecesses in the shaft and hub which is of great advantage where hightorques are to be transmitted. Advantageously, the portions of the diskbetween the individual teeth are deformable, which even further enhancesthe ability of the teeth of the coupling element to conform to theirseats. The coupling element is advantageously made to contact the cap orretainer at only a few points to which end the surface of the coupiingelement facing the cap or retainer is provided with spaced, slightlysuperelevated projections; by this configuration the teeth, in theirresilient deformation, are urged into the slots primarily in thesuperelevated areas, which by and large increases the contact area ofthe coupling element which is available for the transfer of torque.

The deformation forces acting on the coupling element can be greatlyaided by providing the slots and teeth with sloping flanks, i.e. theteeth in cross-section tangential to the shaft are tapered toward saidshaft. Such a profile also facilitates the removal of the couplingelement.

The invention will now be further described with reference to theaccompanying drawings wherein:

FIG. 1 is a longitudinal cross section of one coupling embodiment inaccordance with the invention;

FIG. 2 is an elevational view of the coupling element taken along line11-" of FIG. 1;

FIG. 3 is a longitudinal cross section of another embodiment of acoupling in accordance with the invention; and

FIG. 4 is an elevational view of the'annular coupling element of FIG. 2,taken along line IVIV.

Referring now more particularly to the drawings, in FIG. 1 there isshown a shaft end 1 inserted into a hub or hollow shaft 2. The end facesboth of the shaft end 1 and of the hub 2 are in a common plane. Slots 3are cut into the end faces such that the wedge angle formed by the slotsamounts to about 45. The slots 3 in shaft end 1 and in hub 2 preferablyform a crown, i.e. a circle. The positive coupling between shaft end 1and hub 2 is provided by a coupling element 4 whose teeth arewedge-shaped to match the shape of the slots 3. The coupling element 4,(FIGS. 1 and 2), which is in the form of a continuous annular disk, isheld in place after insertion into slots 3 by a cap 5. The cap 5 isfastened to shaft end 1 by means of the bolt 10 which is represented inFIG. 3, and which can be threaded into a tapped hole 6 in the shaftend 1. To seal the coupling element from the outside, the cap 5 isprovided with a sealing ring 7 which resiliently engages the cylindricalouter surface of the hub 2 when the cap is fastened on.

In another embodiment represented in FIGS. 3 and 4, a coupling element 8is provided which engages the cap at only a few points of contact 9. Thesurface of the annular coupling element 8 which faces the cap 5 isadvantageously provided with slight superelevations or projectionsbetween the points of contact, in the direction of the tips of theteeth. During the transfer of torque, the axial forces produced thusbring about a de sired deformation of the coupling element, resulting inan improvement of the engagement of the coupling element 8 with theslots 3. The pliability of the coupling element is especially enhancedby the fact that the portions of the coupling element which are locatedbetween the individual teeth are also made deformable.

Both the slots 3 and the teeth of the coupling elements 4 and 8 havesloping flanks.

As employed herein, the hub may be of relatively short length or may berelatively longe, i.e. in essence a hollow shaft.

It will be appreciated that the instant specification and examples areset forth by way of illustration and not limitation, and that variousmodifications and changes may be made without departing from the spiritand scope of the present invention.

What is claimed is:

1. In a positive releasable coupling comprising a shaft, a hub on saidshaft, the shaft and hub having end faces lying in substantially thesame plane and being provided with aligned slots cut into their endfaces, a coupling disk provided with teeth complementing and engagingthe slots of said shaft and said hub and thereby coupling said shaft tosaid hub, and means for securing said disk to at least one of said shaftand said hub, the improvement which comprises forming said teeth so thatthey are generally radially directed, said teeth in radial cross-sectionbeing wedge-shaped, the apex of the wedge pointing toward said shaft andsaid hub and being located in the vicinity of the outside surface ofsaid shaft.

2. A coupling according to claim 1, wherein the faces of saidwedge-shaped teeth in radial cross-section making angles of about 45with the plane in which the end faces of said shaft and said hub lie.

3. A coupling according to claim 1, said coupling disk being annular,said disk securing means comprising a cap positioned over said disk andmeans for securing said cap to at least one of said shaft and hub andthereby locking the teeth of said disk into engagement with the teeth ofsaid shaft and said hub.

4. A coupling according to claim 3, wherein the portions of said diskbetween said teeth are deformable.

5. A coupling according to claim 3, wherein said cap or said disk on itsface directed the other is provided with a plurality of projectionswhich constitute the points of contact therebetween and by means ofwhich said disk is forced into its operative position with its teethcoupling said shaft and said hub.

6. A coupling according to claim 5, wherein said projections areprovided on said disk.

7. A coupling according to claim 1, wherein said teeth of said disk incross-section tangential to said shaft are tapered toward said shaft.

8. A coupling according to claim 6, the faces of said wedge-shaped teethin radial cross-section making angles of about 45 with the plane inwhich the end faces of said shaft and said hub lie, said teeth of saiddisk in cross-section tangential to said shaft are tapered toward saidshaft, the portions of said disk between said teeth being deformable,and said cap being secured to said shaft by a bolt.

1. In a positive releasable coupling comprising a shaft, a hub on saidshaft, the shaft and hub having end faces lying in substantially thesame plane and being provided with aligned slots cut into their endfaces, a coupling disk provided with teeth complementing and engagingthe slots of said shaft and said hub and thereby coupling said shaft tosaid hub, and means for securing said disk to at least one of said shaftand said hub, the improvement which comprises forming said teeth so thatthey are generally radially directed, said teeth in radial crosssectionbeing wedge-shaped, the apex of the wedge pointing toward said shaft andsaid hub and being located in the vicinity of the outside surface ofsaid shaft.
 2. A coupling according to claim 1, wherein the faces ofsaid wedge-shaped teeth in radial cross-section making angles of about45* with the plane in which the end faces of said shaft and said hublie.
 3. A coupling according to claim 1, said coupling disk beingannular, said disk securing means comprising a cap positioned over saiddisk and means for securing said cap to at least one of said shaft andhub and thereby locking the teeth of said disk into engagement with theteeth of said shaft and said hub.
 4. A coupling according to claim 3,wherein the portions of said disk between said teeth are deformable. 5.A coupling according to claim 3, wherein said cap or said disk on itsface directed the other is provided with a plurality of projectionswhich constitute the points of contact therebetween and by means ofwhich said disk is forced into its operative position with its teethcoupling said shaft and said hub.
 6. A coupling according to claim 5,wherein said projections are provided on said disk.
 7. A couplingaccording to claim 1, wherein said teeth of said disk in cross-sectiontangential to said shaft are tapered toward said shaft.
 8. A couplingaccording to claim 6, the faces of said wedge-shaped teeth in radialcross-section making angles of about 45* with the plane in which the endfaces of said shaft and said hub lie, said teeth of said disk incross-section tangential to said shaft are tapered toward said shaft,the portions of said disk between said teetH being deformable, and saidcap being secured to said shaft by a bolt.